TABLE 5 ESTIMATES OF 13-MONTH SMOOTH SOLAR ACTIVITY FOR BALANCE OF CYCLE 25 WITH A MEAN CYCLE GIVEN FOR CYCLE 26 TIME 10.7 CM SOLAR FLUX (F10.7) GEOMAGNETIC INDEX (Ap) PERCENTILE PERCENTILE 75.0% 50% 5.0% 95.0% 50% 5.0% 2020.6670 SEP 75.7 75.3 74.6 5.8 5.5 5.3 2020.7503 OCT 77.0 76.4 74.8 6.8 5.7 5.2 2020.8337 NOV 78.6 77.8 75.9 7.6 6.0 5.1 2020.9170 DEC 80.5 79.4 76.9 8.0 6.2 5.0 2021.0003 JAN 82.5 81.2 78.0 8.2 6.2 4.7 2021.0837 FEB 85.1 83.2 78.8 8.8 6.2 4.5 2021.1670 MAR 88.1 85.4 79.3 9.5 6.3 4.1 2021.2503 APR 91.6 87.9 79.8 10.3 6.4 3.7 2021.3337 MAY 95.2 90.6 81.2 11.5 6.7 3.6 2021.4170 JUN 98.3 93.3 83.0 12.4 7.0 3.7 2021.5003 JUL 101.1 96.2 83.3 12.7 7.2 3.7 2021.5837 AUG 105.6 99.3 83.9 12.7 7.4 3.7 2021.6670 SEP 109.3 102.3 85.4 12.1 7.3 3.7 2021.7503 OCT 112.4 105.3 87.1 11.5 7.2 3.8 2021.8337 NOV 114.8 108.3 88.8 10.9 7.1 4.0 2021.9170 DEC 119.2 111.6 90.2 10.5 7.2 4.0 2022.0003 JAN 125.3 115.1 91.3 10.5 7.3 4.3 2022.0837 FEB 128.9 118.7 92.5 10.5 7.6 5.1 2022.1670 MAR 132.8 122.1 93.6 10.8 7.9 5.5 2022.2503 APR 135.3 125.4 95.5 10.7 8.3 6.1 2022.3337 MAY 138.3 128.9 97.8 10.7 8.4 6.2 2022.4170 JUN 142.6 132.2 99.9 11.3 8.7 5.7 2022.5003 JUL 145.5 134.6 101.1 12.1 8.9 5.5 2022.5837 AUG 148.2 136.9 101.5 12.2 9.1 5.3 2022.6670 SEP 152.2 139.4 102.1 12.8 9.4 5.5 2022.7503 OCT 158.4 142.1 103.6 13.7 9.9 5.8 2022.8337 NOV 162.8 144.7 104.6 14.4 10.1 5.5 2022.9170 DEC 166.6 147.0 105.2 14.8 10.2 5.3 2023.0003 JAN 170.5 149.0 106.5 15.3 10.5 5.0 2023.0837 FEB 172.9 150.8 109.4 15.8 10.7 4.7 2023.1670 MAR 174.5 152.3 112.2 16.1 10.8 4.7 2023.2503 APR 177.0 153.7 115.6 16.7 10.9 4.8 2023.3337 MAY 179.1 154.8 119.5 17.7 10.9 4.9 2023.4170 JUN 178.4 155.5 119.7 17.9 11.0 5.0 2023.5003 JUL 176.9 155.9 118.2 17.3 11.1 5.3 2023.5837 AUG 175.7 156.1 116.2 16.9 11.2 5.8 2023.6670 SEP 175.4 156.2 115.0 16.4 11.1 6.0 2023.7503 OCT 175.6 156.4 117.0 15.8 10.9 6.0 2023.8337 NOV 176.2 156.3 118.4 15.8 10.9 6.2 2023.9170 DEC 177.8 156.0 119.6 15.6 11.0 6.3 2024.0003 JAN 178.8 155.3 118.9 14.9 10.8 6.2 2024.0837 FEB 175.3 154.0 117.0 14.1 10.7 6.5 2024.1670 MAR 177.1 153.2 115.2 13.4 10.3 6.7 2024.2503 APR 179.8 152.9 112.7 13.0 9.8 6.1 2024.3337 MAY 177.4 153.2 110.5 13.2 9.6 5.8 2024.4170 JUN 175.0 153.5 109.0 14.1 9.7 5.5 2024.5003 JUL 175.5 153.5 107.7 15.0 9.7 5.2 2024.5837 AUG 176.8 153.1 104.3 15.5 9.8 5.4 2024.6670 SEP 175.0 152.7 101.0 16.2 9.8 5.2 2024.7503 OCT 173.6 152.3 97.6 16.3 9.8 5.2 2024.8337 NOV 173.2 152.1 96.3 15.8 9.9 6.0 2024.9170 DEC 171.1 151.7 95.5 15.5 9.8 6.2 2025.0003 JAN 168.4 150.8 94.2 14.5 9.6 6.3 2025.0837 FEB 167.9 149.6 93.0 14.2 9.6 6.3 2025.1670 MAR 166.9 147.9 91.3 14.2 9.9 7.1 2025.2503 APR 164.7 146.2 90.1 15.1 10.2 7.3 2025.3337 MAY 162.1 144.7 88.1 15.2 10.4 7.4 2025.4170 JUN 159.9 143.5 87.4 15.6 10.7 7.3 2025.5003 JUL 158.0 141.8 87.3 16.1 10.9 7.5 2025.5837 AUG 155.7 139.9 87.4 15.2 10.6 7.3 2025.6670 SEP 152.6 137.6 88.0 15.0 10.7 7.2 2025.7503 OCT 148.9 135.6 88.8 16.0 11.1 7.1 2025.8337 NOV 146.5 133.9 89.3 16.0 11.1 7.2 2025.9170 DEC 145.6 132.5 90.0 15.9 11.2 7.0 2026.0003 JAN 144.2 130.6 90.9 16.0 11.3 7.0 2026.0837 FEB 141.9 128.6 90.8 16.1 11.6 6.9 2026.1670 MAR 139.6 127.2 90.6 15.4 12.0 7.4 2026.2503 APR 138.2 126.0 90.4 15.4 12.3 7.9 2026.3337 MAY 136.3 124.5 90.1 16.1 12.7 8.8 2026.4170 JUN 134.2 122.8 89.6 16.6 13.0 8.7 2026.5003 JUL 132.8 120.8 89.5 16.5 13.4 9.2 2026.5837 AUG 131.7 118.8 88.9 16.8 13.5 9.3 2026.6670 SEP 130.7 117.0 87.8 18.0 13.5 9.4 2026.7503 OCT 129.7 115.0 86.5 18.6 13.4 9.5 2026.8337 NOV 126.8 113.1 85.5 19.0 13.6 9.8 2026.9170 DEC 123.9 111.4 85.3 19.2 13.8 9.8 2027.0003 JAN 122.7 109.9 84.7 19.5 13.9 10.2 2027.0837 FEB 121.0 108.2 84.2 19.2 13.8 9.7 2027.1670 MAR 117.9 106.5 84.1 19.3 13.7 9.5 2027.2503 APR 116.0 105.0 83.2 19.7 13.6 9.4 2027.3337 MAY 114.0 103.2 80.8 19.9 13.3 8.9 2027.4170 JUN 112.2 101.4 79.4 20.3 12.9 7.9 2027.5003 JUL 110.1 99.8 78.0 20.8 12.5 7.0 2027.5837 AUG 107.6 98.5 76.7 21.4 12.3 7.1 2027.6670 SEP 106.3 97.3 75.8 22.0 12.3 7.2 2027.7503 OCT 104.2 96.1 75.3 22.3 12.4 7.2 2027.8337 NOV 103.2 95.3 75.1 22.1 12.1 7.2 2027.9170 DEC 102.6 94.2 74.6 21.5 11.9 7.1 2028.0003 JAN 101.9 92.8 73.8 20.7 11.8 6.5 2028.0837 FEB 100.6 91.6 73.2 20.0 11.8 6.1 2028.1670 MAR 99.7 90.6 72.6 19.8 12.1 5.9 2028.2503 APR 99.6 89.4 72.3 19.5 12.2 5.3 2028.3337 MAY 98.9 88.1 72.1 19.4 12.4 4.9 2028.4170 JUN 98.2 87.0 71.7 19.2 12.7 5.0 2028.5003 JUL 96.5 86.2 71.3 18.7 12.8 5.5 2028.5837 AUG 94.9 85.2 71.1 18.7 12.7 5.9 2028.6670 SEP 93.0 84.2 70.9 18.9 12.5 6.2 2028.7503 OCT 90.3 83.1 70.4 19.0 12.3 6.2 2028.8337 NOV 89.5 82.2 70.3 18.8 12.3 6.4 2028.9170 DEC 88.4 81.5 70.3 18.6 12.4 6.7 2029.0003 JAN 86.9 80.8 70.3 18.3 12.7 7.2 2029.0837 FEB 85.8 80.2 70.4 17.7 13.0 7.5 2029.1670 MAR 85.1 79.5 70.3 16.9 13.0 7.6 2029.2503 APR 84.2 78.8 70.1 16.9 12.7 7.4 2029.3337 MAY 83.3 78.1 70.0 16.9 12.5 7.1 2029.4170 JUN 82.1 77.5 69.9 16.9 12.2 6.8 2029.5003 JUL 81.0 76.9 69.8 17.1 12.2 6.3 2029.5837 AUG 80.6 76.3 69.6 17.5 12.4 6.4 2029.6670 SEP 80.3 75.8 69.5 17.8 12.3 6.6 2029.7503 OCT 79.6 75.3 69.4 17.8 12.2 6.5 2029.8337 NOV 78.3 74.8 69.3 17.5 12.0 6.5 2029.9170 DEC 77.8 74.1 69.1 17.2 11.7 6.3 2030.0003 JAN 76.6 73.4 68.7 16.1 11.2 6.3 2030.0837 FEB 75.4 72.7 68.4 14.5 10.6 6.4 2030.1670 MAR 75.1 72.2 68.1 13.2 10.1 6.2 2030.2503 APR 74.6 71.9 68.0 13.3 9.7 6.0 2030.3337 MAY 73.3 71.6 67.9 12.9 9.2 5.8 2030.4170 JUN 72.9 71.3 67.8 12.6 9.0 5.7 2030.5003 JUL 72.6 71.0 67.8 12.4 8.8 5.7 2030.5837 AUG 72.3 70.7 67.7 12.1 8.7 5.3 2030.6670 SEP 71.8 70.4 67.7 11.4 8.5 4.8 2030.7503 OCT 71.7 70.2 67.4 11.0 8.3 4.4 2030.8337 NOV 71.6 70.0 67.3 10.8 8.1 4.1 2030.9170 DEC 71.6 70.0 67.3 10.8 8.1 4.1 2031.0003 JAN 71.8 70.1 67.2 11.0 8.2 4.0 2031.0837 FEB 72.3 70.4 67.3 11.4 8.4 4.0 2031.1670 MAR 73.0 70.8 67.4 11.5 8.6 3.9 2031.2503 APR 73.1 71.1 67.4 11.7 8.7 3.7 2031.3337 MAY 73.2 71.5 67.6 11.9 8.8 3.5 2031.4170 JUN 74.2 72.1 67.7 12.0 8.9 3.5 2031.5003 JUL 75.6 72.7 67.8 12.1 9.0 3.4 2031.5837 AUG 76.1 73.5 67.9 12.5 9.3 3.4 2031.6670 SEP 77.0 74.3 68.0 12.8 9.6 3.4 2031.7503 OCT 78.2 75.3 68.1 13.3 10.0 3.8 2031.8337 NOV 80.0 76.4 68.4 13.8 10.3 4.2 2031.9170 DEC 82.5 77.8 68.5 14.6 10.6 4.5 2032.0003 JAN 85.7 79.4 68.5 15.7 10.9 4.7 2032.0837 FEB 88.4 81.1 68.5 16.1 11.1 4.8 2032.1670 MAR 91.6 83.1 68.5 16.3 11.3 5.0 2032.2503 APR 94.6 85.2 68.4 16.9 11.4 5.1 2032.3337 MAY 97.2 87.5 68.6 18.0 11.6 5.3 2032.4170 JUN 99.1 89.9 68.7 18.9 11.9 5.4 2032.5003 JUL 103.2 92.5 69.0 19.1 12.1 5.6 2032.5837 AUG 108.1 95.3 69.3 19.2 12.3 5.8 2032.6670 SEP 112.2 98.1 69.4 19.0 12.6 6.0 2032.7503 OCT 116.5 100.9 69.6 18.6 12.7 6.1 2032.8337 NOV 120.0 103.7 70.1 18.5 12.7 6.1 2032.9170 DEC 122.7 106.7 70.8 18.9 12.8 6.1 2033.0003 JAN 125.5 109.8 71.0 18.8 12.9 6.3 2033.0837 FEB 129.4 113.0 71.4 17.8 13.0 6.5 2033.1670 MAR 133.2 116.2 71.7 17.9 13.2 6.7 2033.2503 APR 137.5 119.3 72.3 18.4 13.4 7.1 2033.3337 MAY 143.0 122.6 73.1 19.1 13.7 7.0 2033.4170 JUN 148.7 125.6 73.5 19.6 14.2 7.0 2033.5003 JUL 153.5 128.1 74.3 20.3 14.5 7.1 2033.5837 AUG 157.2 130.2 74.9 20.3 14.5 7.2 2033.6670 SEP 163.0 132.5 75.3 20.3 14.6 7.7 2033.7503 OCT 169.0 135.1 75.8 20.5 14.7 8.1 2033.8337 NOV 173.9 137.6 76.2 20.8 14.8 8.0 2033.9170 DEC 179.8 139.9 76.5 21.2 14.8 8.0 2034.0003 JAN 181.7 141.9 76.5 21.3 14.6 8.4 2034.0837 FEB 184.2 143.7 76.5 21.4 14.6 8.6 2034.1670 MAR 185.0 145.3 76.8 21.6 14.6 8.4 2034.2503 APR 184.8 146.8 77.3 22.0 14.5 8.4 2034.3337 MAY 184.0 147.9 77.8 22.7 14.4 8.6 2034.4170 JUN 183.8 148.7 78.5 22.4 14.1 8.6 2034.5003 JUL 185.2 149.3 79.8 21.3 13.8 8.5 2034.5837 AUG 186.7 149.6 80.6 20.6 13.7 8.3 2034.6670 SEP 187.4 149.9 81.6 20.1 13.6 8.0 2034.7503 OCT 187.1 150.2 83.1 19.7 13.5 7.6 2034.8337 NOV 186.0 150.3 84.6 19.6 13.5 7.5 2034.9170 DEC 186.2 150.3 86.2 19.3 13.5 7.8 2035.0003 JAN 184.1 149.6 87.0 19.1 13.7 7.7 2035.0837 FEB 179.8 148.5 88.2 18.9 13.9 7.6 2035.1670 MAR 176.9 147.7 89.8 18.9 14.0 7.5 2035.2503 APR 178.6 147.5 90.9 19.5 13.9 7.2 2035.3337 MAY 178.2 147.8 93.0 20.4 14.0 7.1 2035.4170 JUN 175.8 148.2 94.3 22.0 14.4 7.1 2035.5003 JUL 173.7 148.2 95.7 23.4 14.7 7.1 2035.5837 AUG 172.3 148.0 96.0 24.0 14.9 7.3 2035.6670 SEP 171.0 147.6 95.6 25.1 15.1 7.3 2035.7503 OCT 169.2 147.2 95.5 25.7 15.3 7.0 2035.8337 NOV 165.4 147.0 97.0 24.9 15.3 7.1 2035.9170 DEC 162.4 146.6 97.8 24.8 15.3 6.7 2036.0003 JAN 159.9 145.8 97.3 24.0 15.3 6.3 2036.0837 FEB 157.8 144.6 96.5 22.2 15.3 6.1 2036.1670 MAR 155.7 143.1 96.4 22.5 15.5 6.3 2036.2503 APR 155.3 141.4 96.9 23.2 15.7 6.5 2036.3337 MAY 155.2 140.0 96.4 23.2 15.7 6.7 2036.4170 JUN 153.7 138.7 95.7 22.7 15.7 7.1 2036.5003 JUL 150.5 137.2 96.3 22.0 15.6 7.6 2036.5837 AUG 146.7 135.5 97.2 21.9 15.7 7.7 2036.6670 SEP 143.8 133.5 96.3 22.7 15.9 8.1 2036.7503 OCT 140.4 131.8 94.6 23.6 16.2 8.7 2036.8337 NOV 137.4 130.4 93.8 23.8 16.4 8.9 2036.9170 DEC 136.7 129.2 93.6 23.8 16.6 9.3 2037.0003 JAN 136.0 127.5 91.8 23.8 16.6 9.7 2037.0837 FEB 134.8 125.7 88.5 23.4 16.6 10.1 2037.1670 MAR 133.8 124.4 88.0 22.5 16.5 10.5 2037.2503 APR 134.1 123.3 88.7 22.7 16.4 10.7 2037.3337 MAY 132.8 121.9 87.3 22.9 16.5 11.5 2037.4170 JUN 130.7 120.3 86.3 23.0 16.6 11.7 2037.5003 JUL 129.7 118.5 85.7 22.4 16.7 11.9 2037.5837 AUG 129.1 116.7 84.9 21.5 16.5 11.9 2037.6670 SEP 126.6 115.0 83.7 21.2 16.3 11.7 2037.7503 OCT 125.2 113.1 82.7 21.7 16.1 11.4 2037.8337 NOV 124.7 111.2 82.3 21.7 16.1 11.5 2037.9170 DEC 123.6 109.6 82.2 22.1 16.1 11.4 2038.0003 JAN 122.1 108.0 82.0 22.5 16.2 11.2 2038.0837 FEB 120.1 106.4 81.0 22.3 16.2 11.0 2038.1670 MAR 118.3 104.8 80.6 22.3 16.0 10.8 2038.2503 APR 116.2 103.4 80.6 22.7 15.8 10.7 2038.3337 MAY 114.3 101.8 80.0 22.9 15.5 10.6 2038.4170 JUN 111.1 100.2 79.1 23.4 15.3 10.3 2038.5003 JUL 109.5 98.7 77.7 24.0 15.0 10.1 2038.5837 AUG 107.9 97.5 75.6 24.7 14.9 10.1 2038.6670 SEP 106.4 96.3 74.6 25.3 14.8 10.1 2038.7503 OCT 104.4 95.2 74.1 25.4 14.8 10.5 2038.8337 NOV 103.0 94.3 73.8 25.3 14.7 10.4 2038.9170 DEC 102.0 93.3 73.5 24.8 14.5 10.2 2039.0003 JAN 100.5 92.1 73.1 23.9 14.3 10.0 2039.0837 FEB 98.9 91.0 72.7 23.0 14.1 9.4 2039.1670 MAR 98.2 90.0 72.0 22.5 14.2 8.8 2039.2503 APR 97.9 89.0 71.4 22.1 14.2 8.1 2039.3337 MAY 97.5 87.8 71.1 21.8 14.3 7.5 2039.4170 JUN 97.0 86.8 70.8 21.4 14.5 7.4 2039.5003 JUL 95.7 85.9 70.6 20.8 14.4 7.7 2039.5837 AUG 94.8 85.1 70.6 20.0 14.3 8.1 2039.6670 SEP 93.0 84.1 70.4 20.0 14.1 8.5 2039.7503 OCT 90.8 83.0 69.9 20.2 13.9 8.5 2039.8337 NOV 89.4 82.0 69.6 19.8 13.7 8.5 2039.9170 DEC 88.2 81.3 69.5 19.4 13.6 8.4 2040.0003 JAN 86.7 80.6 69.5 18.9 13.6 8.4 2040.0837 FEB 85.9 80.0 69.3 18.2 13.6 8.1 2040.1670 MAR 85.2 79.2 69.2 17.3 13.5 7.7 2040.2503 APR 83.9 78.5 68.8 17.3 13.3 7.1 2040.3337 MAY 82.8 77.8 68.6 17.4 13.2 6.8 2040.4170 JUN 81.8 77.2 68.4 17.5 13.1 6.6 2040.5003 JUL 81.2 76.6 68.4 17.5 12.9 6.5 2040.5837 AUG 80.7 76.1 68.5 17.7 12.9 6.6 2040.6670 SEP 80.5 75.6 68.5 18.0 12.7 6.5 2040.7503 OCT 79.2 75.1 68.5 17.9 12.6 6.4 2040.8337 NOV 77.9 74.6 68.4 17.6 12.3 6.4 2040.9170 DEC 77.2 73.9 68.3 17.3 12.0 6.2 2041.0003 JAN 76.7 73.2 68.0 16.3 11.7 6.1 2041.0837 FEB 75.8 72.6 67.8 14.9 11.2 6.0 2041.1670 MAR 75.3 72.1 67.7 13.8 10.9 6.1 2041.2503 APR 74.4 71.8 67.6 13.9 10.5 6.2 2041.3337 MAY 73.3 71.5 67.5 13.6 10.2 6.2 2041.4170 JUN 73.2 71.1 67.3 13.2 9.8 6.0 2041.5003 JUL 72.4 70.8 67.1 12.9 9.5 5.9 2041.5837 AUG 71.7 70.5 67.1 12.6 9.3 5.8 2041.6670 SEP 71.6 70.2 67.0 11.9 9.1 5.7 2041.7503 OCT 71.8 70.0 67.0 11.4 8.9 5.2